The U.S. Department of Justice is reviewing whether and how market-leading online platforms have achieved market power and are engaging in practices that "have reduced competition, stifled innovation, or otherwise harmed consumers."

The Department’s review will consider the concerns that consumers, businesses, and entrepreneurs have expressed about search, social media, and some retail services online. The Department’s Antitrust Division is conferring with and seeking information from the public, including industry participants who have direct insight into competition in online platforms, as well as others.

“Without the discipline of meaningful market-based competition, digital platforms may act in ways that are not responsive to consumer demands,” said Assistant Attorney General Makan Delrahim of the Antitrust Division. “The Department’s antitrust review will explore these important issues.”

The goal of the review is to "assess the competitive conditions in the online marketplace in an objective and fair-minded manner and to ensure Americans have access to free markets in which companies compete on the merits to provide services that users want," the Justice Department said in a statement.

If violations of law are identified, the Department will proceed appropriately to seek redress.

The Justice Department did not identify specific companies but said the review would consider concerns raised about “search, social media, and some retail services online” — an apparent reference to Alphabet Inc, Amazon.com Inc and Facebook Inc, and potentially Apple Inc.

The announcement comes just a day before the Federal Trade Commission is set to announce a $5 billion penalty to Facebook for failing to properly protect user privacy.